As is generally known, various kinds of cooking vessels are used for the purpose of cooking food in a restaurant or at home. Such cooking vessels include frypans or pans with various sizes and shapes, and may be selectively used in accordance with the characteristics of the food to be cooked.
Such a cooking vessel is generally formed of a metal material having preset thermal conduction and strength, and may be provided with a handle that is formed on one side or both sides of the cooking vessel so that a user can safely grasp the handle and a cover that is provided to prevent a loss of heat during cooking and to prevent the food being cooked from spattering out of the cooking vessel.
The metal material used to manufacture the cooking vessel may be stainless steel, casting material, or an aluminum alloy, and the inner surface of the cooking vessel is coated with a ceramic coating agent to show non-stick function. However, since the ceramic coating agent has the problem that the food being cooked is apt to stick thereto after a predetermined use period, a Teflon coating agent has been developed and widely used.
The Teflon coating agent may include PFOA (Perfluorooctanoic Acid) in accordance with the kind thereof, and the PFOA is an environmental hazardous material that is regulated as a use-restricted item in advanced nations in which noxiousness of the PFOA has been deeply recognized. Accordingly, a cooking vessel coated with a ceramic coating agent that is innoxious to a human body is recently preferred.
As described above, the ceramic coating agent and the Teflon coating agent in the related art have advantages and disadvantages. In common, they have the problems that the non-stick function thereof deteriorates due to scratches that are repeatedly formed on the surface of the cooking vessel in the cooking or cleaning process after a predetermined use period.
Further, in order to maintain the fine appearance, a pattern layer having various kinds of patterns is formed on an outer surface of the cooking vessel, and concentric projections are formed on a bottom surface of the cooking vessel that comes in direct contact with fire to prevent slipping.
In the case of forming the patterns, offset printing, silk screening printing, and transfer printing using transfer sheets may be used. The offset printing has advantages that printing can be performed even on a curved portion of the cooking vessel, but also has disadvantages that the expensive printing cost causes the manufacturing cost of the cooking vessel to be increased. Further, the silk screening printing or the transfer printing has advantages of inexpensive printing costs, but also has disadvantages that it is not possible to perform printing on the curved portion of the cooking vessel to restrict the finishing process.
As described above, the patterns formed in the related art has no expectable effect except for maintaining of the fine appearance of the cooking vessel, and the concentric projections that are formed on the bottom surface to prevent slipping have the problem that it is difficult to process the projections together during the above-described printing process. Further, since the projections are formed limitedly on the bottom surface of the cooking vessel, it is difficult to expect an increased heat transfer area.